Constraints [Guest Editor´s Introduction]

This issue of IEEE Intelligent Systems includes an interview with Pierre Haren and Mehmet Dincbas, the heads of ILOG and Cosytec, two major commercial vendors of constraint technology. Constraint technology has made a significant industrial impact. Many industrial scheduling problems use constraints, especially problems that require fine-grained scheduling. Personnel scheduling and transportation problems are two industrial applications where constraint technology is increasingly the technology of choice. In putting together this special issue, we opted for a variety of diverse applications of constraint technology. Each application emphasizes different advantages of the technology. As a whole, the applications give an impression of the expressive power of constraints and the extraordinary adaptability of constraint solving as a mechanism for constructing complex algorithms.